OTOY Forums

Hello everybody,

similar to this thread viewtopic.php?f=30&t=61606 I have a problem with "invisible" lights still casting a shadow onto another object. But different to that thread I cannot set the lights opacity to 0 as I still want it to be visible in reflections.

I have also tried light linking by setting the four lights to light pass ID 2 which I then subtraced from the ground via an octane tag. Although this works for the light of the light sources, they still seem to block other lights, although I have set them to be invisible to shadows.

What am I missing?
Can these artefacts be removed in one render?


Cheers & thanks for any input
Ralf

EDIT: Added Cinema 4D example file with a slightliy different light setup.

Try angling your lights so that those artefacts are out of frame. I believe that they are the result of the rectangle shape, with less light coming of the edges, making it appear that there are shadows there. You can also try more 3D shapes, such as spheres and cubes.

Thanks Jay for your suggestion but moving the lights causes some of their reflection on the model to be at least partially clipped by the floor.

Attached you can find an extreme example:
When I want to light the object from below I do get a shadow on the floor. Following your suggestion I would need to move the light source along it´s normal y-direction away from the model and scale it up to retain most of it´s reflection. Unfortunately this is not feasible as the light would then be completely blocked by the floor.
Similar things do happen to other light sources as they are placed further away from the model.

Might there be another approach to do this without additional passes?

Cheers & thanks
Ralf

Via Brent Vowles and Raphael Rau pointing me in the right direction on facebook I found that the culprit was that I had set the lightsource´s type to texture.
Setting it to blackbody, changing it´s opacity to "0" and enabling "transparent emission" was the sollution.